import 'dart:convert';

import 'package:yumi/shared/data_sources/models/sc_music_mode.dart';
import 'package:yumi/shared/data_sources/sources/local/data_persistence.dart';

class RoomMusicRepository {
  List<SCMusicMode> loadSongs() {
    final raw = DataPersistence.getUserRoomMusic();
    if (raw.trim().isEmpty) {
      return <SCMusicMode>[];
    }
    try {
      final decoded = jsonDecode(raw);
      if (decoded is! List) {
        return <SCMusicMode>[];
      }
      final songs =
          decoded
              .map((item) => SCMusicMode.fromJson(item))
              .where((item) => item.hasPlayablePath)
              .toList()
            ..sort((a, b) {
              final sort = a.sortIndex.compareTo(b.sortIndex);
              if (sort != 0) {
                return sort;
              }
              return a.addedAt.compareTo(b.addedAt);
            });
      return _normalizeSort(songs);
    } catch (_) {
      return <SCMusicMode>[];
    }
  }

  Future<bool> saveSongs(List<SCMusicMode> songs) {
    final normalized = _normalizeSort(_dedupeSongs(songs));
    return DataPersistence.setUserRoomMusic(
      jsonEncode(normalized.map((item) => item.toJson()).toList()),
    );
  }

  List<SCMusicMode> _dedupeSongs(List<SCMusicMode> songs) {
    final seen = <String>{};
    final result = <SCMusicMode>[];
    for (final song in songs) {
      final key = song.id.isNotEmpty ? song.id : song.localPath;
      if (key.isEmpty || !seen.add(key)) {
        continue;
      }
      result.add(song);
    }
    return result;
  }

  List<SCMusicMode> _normalizeSort(List<SCMusicMode> songs) {
    return List<SCMusicMode>.generate(
      songs.length,
      (index) => songs[index].copyWith(sortIndex: index),
      growable: true,
    );
  }
}